High resolution NMR spectroscopy will be applied to the investigation of the structure of peptides, proteins, and complexes between them. Individual topics to be studied will include: (1) the structure of Troponin C, using mercuryaryl reagents for modifying the -SH group, and application of the nuclear Overhauser effect to determine the identity of nearby side-chains; (2) the conformation of the N-terminal octapeptide from the beta-chain of sickle cell hemoglobin, and its site of interaction with sickle cell hemoglobin; (3) the conformation of Brady kinin in solution. The utility and limitations of the nuclear Overhauser effect, as well as 2H resonance and the effects of 2H substitution in peptides, will be explored in the course of the studies.